Public Types | |
| typedef void | output_function_type (std::ostream &s, const Variable &v) |
| Type of output functions. | |
Public Member Functions | |
| Variable (dimension_type i) | |
Builds the variable corresponding to the Cartesian axis of index i. | |
| dimension_type | id () const |
| Returns the index of the Cartesian axis associated to the variable. | |
Static Public Member Functions | |
| void | set_output_function (output_function_type *p) |
| Sets the output function to be used for printing Variable objects. | |
| output_function_type * | get_output_function () |
| Returns the pointer to the current output function. | |
Related Functions | |
| (Note that these are not member functions.) | |
| std::ostream & | operator<< (std::ostream &s, const Variable &v) |
| Output operator. | |
| bool | less (Variable v, Variable w) |
| Defines a total ordering on variables. | |
An object of the class Variable represents a dimension of the space, that is one of the Cartesian axes. Variables are used as base blocks in order to build more complex linear expressions. Each variable is identified by a non-negative integer, representing the index of the corresponding Cartesian axis (the first axis has index 0).
Note that the ``meaning'' of an object of the class Variable is completely specified by the integer index provided to its constructor: be careful not to be mislead by C++ language variable names. For instance, in the following example the linear expressions e1 and e2 are equivalent, since the two variables x and z denote the same Cartesian axis.
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